Finkl, C.W. and Makowski, C., 2021. Alongshore classification and super domain delineation of coastal belts based on interpretation of biophysical catenary sequences observed from satellite images. Journal of Coastal Research, 37(1), 1–25. Coconut Creek (Florida), ISSN 0749-0208.

The cross-shore classification of coastal belts, facilitated by the interpretation of biophysical features from satellite imagery, is an adjunctory approach to traditional alongshore classification procedures. Methods such as the Biophysical Cross-shore Classification System (BCCS) (Finkl and Makowski, 2020a) and the Coastal Belt Linked Classification (CBLC) (Finkl and Makowski, 2020d) not only provide insight into cross-shore natural ecological variability and zonation, but also emphasize eco-geomorphological linkages so that shore-normal transitions and successions can be delineated and understood. The discernment of numerous cross-shore biophysical transect codifications in a satellite image seascape scene (referred to as either BCCS or CBLC code sequences) results in coastal belt segmenting that identifies offshore, nearshore, inshore, and onshore similarities and differences. This, in turn, can be correlated alongshore by establishing the swath widths of each cross-shore transect as an individual domain. Data integration and interpretation processes are similarly applied as procedural management of geological borehole (well) logs to determine drilling and petrophysical parameters. This study demonstrates that once all individual alongshore domains are interpreted for a specific coastal area, they can be collectively amalgamated and concised to create a universal alongshore super domain for the entire coastal belt. The advantage of constructing a Concised Alongshore Super Domain is that the procedure provides a sagacious and rational basis for swath alongshore classification of coastal belts. This study shows the effective use of this methodology across coastal belts of varying latitudes, as the interpolation of shore-normal ecological sequences validates the cross-shore correlation between transects and can result in a universal alongshore classification process in the form of super domains for coastal belts worldwide.

Moore, S.; Heise, E.A.; Grove, M.; Reisinger, A., and Benavides, J.A., 2021. Evaluating the impacts of dam construction and longshore transport upon modern sedimentation within the Rio Grande Delta (Texas, U.S.A.). Journal of Coastal Research, 37(1), 26–40. Coconut Creek (Florida), ISSN 0749-0208.

The modern Rio Grande delta system has experienced a century of dam construction, water removal for irrigation and municipal use, and land use modifications that have dramatically reduced its sediment load. This study examines whether damming has sufficiently limited delivery of upstream sediment to permit locally eroded sources and/or littoral transport along the coast to influence the provenance signal of the Rio Grande delta. Changes in sediment provenance within the Rio Grande's delta can be detected and quantified by measurement of detrital zircon Uranium–lead dating age distributions. Previous provenance studies indicate that modern Rio Grande river sand upstream of Falcon Dam is enriched in zircon derived from Oligocene volcanic fields within the southern Rocky Mountains and the Sierra Madre Occidental. Results from this study indicate that the abundance of Oligocene zircon is depleted in the modern Rio Grande delta relative to river sand sampled upstream of Falcon Dam. Mixing calculations performed with age distributions representative of Eocene–Miocene fluvial sedimentary deposits that crop out downstream of the dam indicate that erosional reworking of these materials has significantly altered sedimentary provenance within the delta. The importance of north-directed longshore transport along the Mexican (Tamaulipas-Veracruz) Gulf Coast was also evaluated. The absence of distinctive zircon from the Trans Mexican volcanic belt and the basement of southern Mexico within the barrier islands of the Rio Grande delta support previous conclusions that sediment transport along the Tamaulipas-Veracruz shelf is highly compartmentalized and restricted in lateral movement due to seasonal variation in littoral current polarity, topographic barriers along the shelf, and other phenomena. Nevertheless, the results of this study demonstrate that construction of dams across rivers such as the Rio Grande is capable of sufficiently limiting upstream sediment transport to permit otherwise unimportant local sources to dominate sand provenance within their delta systems.

El Waheidi, M.M.; Ghrefat, H.; Qaysi, S.; Batayneh, A.T.; Russo, G.; Jallouli, C.; Badhris, O.; Maeshi, T.; Elawadhi, E.A., and Bahkali, I., 2021. Hydrogeophysical characterization of the coastal aquifer system in the northeast Gulf of Aqaba (Saudi Arabia): An investigation in the context of groundwater resources management. Journal of Coastal Research, 37(1), 41–51. Coconut Creek (Florida), ISSN 0749-0208.

A hydrogeophysical investigation has been conducted along the NE part of the Gulf of Aqaba coast that covered a total area of about 40 km². The area represents a vital part of the ambitious national project NEOM that is a major outcome of the Saudi Arabia's strategic Vision 2030. The research aimed to provide decision makers with the characteristics of the main aquifer in the area in terms of its lateral and vertical extensions and quality of groundwater. To achieve the set objectives, an integrated methodology has been applied that is based on using electrical resistivity tomography (ERT) method and hydrochemical analysis of groundwater samples from the coastal aquifer collected via six shallow water wells. A total of 17 ERT profiles have been conducted; each has a maximum length of 350 m with a distance from the coast in the range 300–800 m. The derived two-dimensional and quasi-three-dimensional resistivity models successfully mapped the lateral and vertical extensions of the aquifer, determined the depth to the saturated zone, and provided the bulk resistivity of the aquifer. A basement uplift has been detected, indicating that the coastal aquifer is separated into northern and southern zones. The results related to the quality of groundwater were supported by the chemical analysis of the groundwater samples, which showed high concentrations of TDS and Cl^–; this indicates a probable partial mixing of the groundwater with seawater. Water-quality index showed that the groundwater is unsuitable for drinking purposes, whereas it is classified as partially adequate for irrigation.

Xu, Y.; Liao, B.; Jiang, Z.; Xin, K.; Xiong, Y., and Guan, W., 2021. Emission of greenhouse gases (CH₄ and CO₂) into the atmosphere from restored mangrove soil in South China. Journal of Coastal Research, 37(1), 52–58. Coconut Creek (Florida), ISSN 0749-0208.

Mangroves are a special ecosystem in tropical and subtropical coastal areas. Currently, it is not adequately understood whether soils in restored mangroves are a substantial source of greenhouse gases. The objectives of this study were to determine whether restored mangrove soils are a substantial source of carbon dioxide (CO₂) and methane (CH₄) and to identify environmental factors affecting soil CO₂ and CH₄ fluxes in mangrove sites. From August 2019 to January 2020, CO₂ and CH₄ flux surveys were conducted in soils at four planted mangrove sites, dominated by Excoecaria agallocha, Kandelia obovata, Bruguiera gymnorrhiza, and Hymenocallis littoralis, respectively, in a mangrove reserve in southern China. The results showed that the CO₂ and CH₄ flux ranges of the four mangrove sites were 0.9432–1.7892 mmol m^–2 h^–1 and –0.104 to 0.845 µmol m^–2 h^–1, respectively. Soil CO₂ flux was strongly positively (p < 0.01) correlated with soil organic carbon content and positively correlated (p < 0.05) with soil total N content, temperature, and redox potential. CH₄ flux was positively correlated with soil temperature. The results confirm that these restored mangrove soils are only a small greenhouse gases source to the atmosphere.

Helm, C.W.; Cawthra, H.C.; De Vynck, J.C.; Dixon, M., and Stear, W., 2021. Elephant tracks: A biogenic cause of potholes in Pleistocene South African coastal rocks. Journal of Coastal Research, 37(1), 59–74. Coconut Creek (Florida), ISSN 0749-0208.

The Cape south coast of South Africa contains extensive outcrops of Pleistocene aeolianite and cemented foreshore deposits. More than 250 vertebrate tracksites have been identified in these deposits, including 35 elephant tracksites. In places, where large palaeosurfaces are occasionally exposed, numerous potholes are evident on the remains of what is most likely a palaeo-coastline. Features suggestive of elephant tracks are apparent on such surfaces and in overlying layers. In order to develop, potholes require a disturbance or depression in the surface to act as a “pothole-precursor” on which erosive forces can act. While elephant tracks or similar biogenic origins for potholes have not previously been described, such an explanation appears plausible for at least some pothole features in areas known to have harboured elephants or other large vertebrate trackmakers when these surfaces were composed of unconsolidated sand. Four sites on the Cape south coast are examined and described. Evidence for use of beaches as travel corridors for elephants is described, and candidate Pleistocene trackmaker species are considered. The age of these palaeo-surfaces is considered to range from Marine Isotope Stage 11 to Marine Isotope Stage 5. It is concluded that depressions formed by elephant tracks should be considered as a precursor for the formation of potholes on suitable Pleistocene surfaces in littoral zones.

Kamara, M. and Kamruzzaman, M., 2021. Effects of thinning on aboveground net primary productivity in overcrowded mangrove Kandelia obovata stands. Journal of Coastal Research, 37(1), 75–81. Coconut Creek (Florida), ISSN 0749-0208.

Litter plays a significant role in nutrient cycling in mangrove forest. Natural or artificial thinning processes can have various impacts on litter production, thereby varying nutrient fluxes. The effects of various thinning intensities on litterfall dynamics were evaluated over a 4-year study period in overcrowded Kandelia obovata stands. To quantify litterfall, two litter traps were placed in each plot (a total of six litter traps in each transect) composed of one naturally thinned control plot and two artificially thinned plots where 30% and 15% of stems were removed at the beginning of the experiment. Annual litterfall production showed a decreasing trend with increasing thinning intensity. Results showed that there was no significant difference in aboveground biomass production among the different plots at the last year of the study period. Thinning can be an important tool for silvicultural practices and forest productivity in terms of litterfall and aboveground biomass.

Wan, Z.; Luo, S.; Huang, S.; Sun, Z.; Zou, Z., and Lu, X., 2021. Large eddy simulation of bubbles on the ocean surface under high-speed winds. Journal of Coastal Research, 37(1), 82–91. Coconut Creek (Florida), ISSN 0749-0208.

Waves break under high-speed wind conditions, and a large number of bubbles are generated. These bubbles have an important influence on the magnitude of air–sea exchanges, including but not limited to the transfer of momentum, mass, and heat. Because of current technical limitations, it is still difficult to observe the motion and distribution of bubbles in the ocean under high-speed wind conditions. In this study, the large eddy simulation technique is used to simulate the motions and distributions of 15 bubbles with different radii at high wind speeds under Langmuir circulation. The simulation results show that under high wind speeds, the bubble radius is an important factor affecting the movement of bubbles in the ocean. Large-radius bubbles quickly escape from the seawater because of buoyancy or break into smaller-radius bubbles. At the same time, the results also show that the bubbles are mainly distributed in the near-surface layer and are concentrated in the downflow region of the Langmuir circulation.

Sogut, E. and Farhadzadeh, A., 2021. Numerical study of longshore variation in beach morphodynamics along Eastern Lake Erie shoreline due to seiche. Journal of Coastal Research, 37(1), 92–103. Coconut Creek (Florida), ISSN 0749-0208.

Extreme coastal events and abrupt changes in atmospheric pressure in an enclosed or semi-enclosed basin can trigger low-frequency water surface oscillations known as seiches. This exploratory study numerically quantifies the effects of seiche on morphological changes along the eastern Lake Erie shoreline. The quantification is made by simulating the hydrodynamics of the lake using a coupled circulation and spectral wave model (ADCIRC+SWAN), providing the flow boundary conditions to the two-dimensional nearshore morphodynamic model, XBeach. The process-based XBeach model is used to simulate the nearshore morphological variations under two water-level conditions: the lake's actual water level and the synthetically generated seiche-free water level. The XBeach model is cross-calibrated using the process-based nearshore morphodynamic model, CSHORE, which was extensively validated using lab and field data. It is found that the seiching motions have a contribution of ∼1.5% to the erosion of beaches along the 2-km stretch of the shoreline in eastern Lake Erie shoreline.

Han, Z.; Xie, H.; Li, H.; Li, W.; Wen, X., and Xie, M., 2021. Morphological evolution of the Lingding Channel in the Pearl River Estuary over the last decades. Journal of Coastal Research, 37(1), 104–112. Coconut Creek (Florida), ISSN 0749-0208.

Dominated by the combined influence of fluvial and marine processes as well as human activities, estuarine regions are facing serious challenges, especially Lingding Bay in the Pearl River Estuary (PRE). The Lingding Channel is the main estuarine channel in Lingding Bay, and it connects to the outer sea, so its morphological evolution is very critical for navigation and estuarine management. Underwater topography data and remote sensing images of Lingding Bay in the PRE were employed to examine the morphological evolution of the Lingding Channel over the last decades (1965–2016). The results show that the West Shoal in Lingding Bay has extended eastward through a silting process caused by land reclamation and sediment discharge from the Pearl River; consequently, the Lingding Channel has become narrow. Additionally, the Lingding Channel has become deep because of channel regulation activities. In the last 10 years, large-scale sand-dredging activities at the Fanshi Shoal have deepened the shallow shoal near Lingding Channel, and many large and deep holes have formed with irregular shapes. In summary, drastic changes have occurred in the landforms near the Lingding Channel, which will likely influence the future stability of the channel. This represents a new and concerning challenge. Furthermore, sand-dredging activities could also produce large amounts of turbid water that could be transported into the Lingding Channel and increase the siltation rate.

Li, J.; Lu, J.; Wang, J.; Wang, Y.; Lai, J., and Yu, K., 2021. Do diploid and haploid solitary cells of Phaeocystis globosa support the same copepod grazing, survival, egg production, and hatching success? Journal of Coastal Research, 37(1), 113–121. Coconut Creek (Florida), ISSN 0749-0208.

The food quality of phytoplankton affects the reproductive success of predators. Phaeocystis globosa blooms have negative effects on marine environments. However, the quality of P. globosa cells for predators is still under debate. The hypothesis that the nutritional value of diploid and haploid solitary cells would be different for the calanoid copepod predator Parvocalanus crassirostris was tested. The fatty acid compositions of diploid and haploid solitary cells and the effects of these cells on copepod grazing, survival, egg production, and hatching success were evaluated. In contrast to haploid solitary cells, diploid solitary cells did not contain C20:5ω3 (EPA) and C22:6ω3 (DHA) and were deficient in polyunsaturated fatty acids. Parvocalanus crassirostris individuals ingested more diploid than haploid cells. Egg hatching success was similar between the diets with diploid and haploid cells. Copepod survival and egg production were strongly inhibited by feeding on diploid cells. In contrast, they were high when copepods fed on haploid cells, reaching levels as high as those observed when the copepods fed on optimal diets of Isochrysis galbana and the diatom Thalassiosira weissflogii. The results suggest that diploid solitary cells of P. globosa are a poor food, whereas haploid solitary cells of this species are a nutrient-rich food for copepods.

Shu, Q.; Zhao, Z.; Zhao, Y.; Chen, Y., and Zhang, M., 2021. Magnetic properties of late Cenozoic sediments in the Subei Basin: Implications for the Yangtze River run-through time. Journal of Coastal Research, 37(1), 122–131. Coconut Creek (Florida), ISSN 0749-0208.

The Subei Basin is situated in the lower reaches of the Yangtze and Huai Rivers. In this study, samples were selected from the XH-2 borehole near the subsidence center of the Subei Basin, and modern sediments from the lower reaches of the Yangtze and Huai Rivers. The aim of this study is to decipher the evolution of the regional river system and the formation of the Yangtze River's Three Gorges through the analyses of paleomagnetism, mass susceptibility, and magnetic minerals. The results show that the river system in the Subei Basin experienced several major upheavals. (1) During 4.76–4.2 million years before present (Ma BP), the Yangtze River flowed through the study area in the vicinity of the XH-2 location; (2) During 4.2–2.2 Ma BP, the Yangtze River had migrated from the study area, and the Huai River flowed through the area; (3) During 2.2–0.55 Ma BP, the Yangtze River flowed through the area again; (4) During 0.55–0.12 Ma BP, the Yangtze River and Huai River alternatively influenced the study area; and (5) Since 0.12 Ma BP, the Yangtze River withdrew from the Subei Basin entirely, and the Huai River flows through the XH-2 position again. The Yangtze River sediment in the bottom of the XH-2 borehole indicates that the time of formation of the Three Gorges of the Yangtze River is probably greater than or equal to 4.76 Ma BP. This estimated time is earlier than the previous conclusions of an Early Pleistocene run-through time for the Yangtze River.

Guo, H.; Bahrian, F.; Zhang, W.; Sun, C., and Hu, J., 2021. Large eddy simulation of wake formation around a free surface–piercing circular cylinder. Journal of Coastal Research, 37(1), 132–142. Coconut Creek (Florida), ISSN 0749-0208.

Numerical simulation of flow past a free surface–piercing circular cylinder using large eddy simulation was performed at Reynolds number Re = 2.7 × 10⁴ and Froude number Fr = 0.8. Commercially available code in ANSYS Fluent was used to investigate the free surface and underlying vortical structures. The dynamic Smagorinsky subgrid-scale model and volume of fluid method for capturing the free surface were used in the simulation. The mean velocities and interface height from the simulation are in good agreement with the available experimental data. The organized Karman vortex generation in deep flow was found to attenuate near the free surface. The overall force developed on the cylinder also decreased due to the presence of the free surface. The simulation shows that the vortical structures present in the flow correlate with the mean parameters of the free surface. Vorticity magnitude and Reynolds shear stress were found to show significantly different behavior close to the free surface as compared to that in deep flow.

Gao, K.; Tian, J.; Wu, Y.; Mei, P.; Zhang, Z.; Jönsson, M., and Brandt, I., 2021. Induction of cytochrome P4501 genes by various inducers in rainbow trout (Oncorhynchus mykiss). Journal of Coastal Research, 37(1), 143–148. Coconut Creek (Florida), ISSN 0749-0208.

Juvenile rainbow trout is widely found in various aquatic systems, such as freshwater, coastal, and marine habitats all over the world. Expression patterns of the cytochrome P4501 (CYP1) genes exposed to various stressors in such fish could be informative and useful in biomonitoring. In the present study, the induction of CYP1 in rainbow trout by indigo, humic acid (HA), and benzo(a)pyrene (BaP) was studied through a 12-hour exposure experiment by using rainbow trout as an experimental object. First, 7-ethoxyresorufin O-deethylase (EROD) activity and CYP1 expression levels in fish exposed to different concentrations of indigo were analyzed. The EROD activities in fish gills were greatly affected by the concentration of indigo (1, 18, 50, and 80 nM). The expression level of CYP1A1 and CYP1A3 in gills was higher compared with CYP1B1 and CYP1Cs. Second, the gill EROD activity and CYP1 mRNA expressions levels were compared when induced by indigo, HA, and BaP at the same concentration (1 nM). Results indicated that rainbow trout were sensitive to all three inducers. Among them, the HA affected CYP1A1 and CYP1A3 most obviously. CYP1A, as an important biomarker, was more sensitive than CYP1B and CYP1C to those inducers. The observed effects of the different CYP1 inducers could provide a useful tool for monitoring of AhR-active pollutants in the aquatic environment.

Shen, C.; Qian, J.; Chen, X.; Xie, F., and Zhu, J., 2021. Nonlinear behavior of marine soil on the dynamic stability of the upper wharf structures: A numerical simulation approach. Journal of Coastal Research, 37(1), 149–155. Coconut Creek (Florida), ISSN 0749-0208.

This paper investigates the influence of mechanical behavior of marine soil on the dynamic stability of the upper wharf. A series of triaxial consolidation undrained shear tests and one-dimensional consolidation compression tests was conducted to analyze the influence of fine particle content on the nonlinear behavior of marine soil. It was found that the relationship between stress and strain, the undrained shear strength, and residual strength of soil samples strongly correlated with the content of fine particles. In addition, the content of illite soil had a significant impact on the characteristic of the stress–strain curves, with a threshold of about 10%. A numerical model of the foundation-pile-superstructure under wave load was established. The results showed that the dynamic response of a wharf under wave load depended on the strength and nonlinear behaviors of the marine soil foundation. The strain-softening foundation with high peak strength led to more damage on the wharf. However, the strain-hardening characteristics resulted in more damage on the wharf when the peak strength was low. This suggests that the mechanical properties of soil foundation should be taken into account for the long-term durability and stability in the design of the wharf.

Zhang, Y.; Yan, S.; Wang, W., and Wang, M., 2021. Habitat use by fish across tidal cycles in a tropical estuarine mangrove ecosystem (Dongzhaigang Bay, Hainan, China). Journal of Coastal Research, 37(1), 156–167. Coconut Creek (Florida), ISSN 0749-0208.

Mangroves wetlands are recognized as nursery areas for large numbers of marine organisms. Yet, many properties of this nursery function remain poorly understood. In this study, the seasonal use of a tropical mangrove bay by fish assemblages over tidal cycles was investigated in 2009. Fish were sampled using centipede nets from three sites (located in the mouth, middle, and top of the bay) at Dongzhaigang Bay, Hainan, China. At each site, three replicates were sampled from each of the three different habitat types (i.e. vegetated area, creek, and mudflat). A generalized linear mixture model was used to explore the spatial and temporal variations in fish assemblages. The results showed that fish species richness, abundance, and biomass per sampling unit were significantly lower in the vegetated areas and mudflats than in the creeks. In the vegetated areas, fish species richness, abundance, and biomass per sampling day were significantly higher during spring tides than during neap tides. However, a similar pattern was not found both along the creeks and on the mudflats. In addition, tidal height showed a positive effect on biomass per sampling unit, especially in the vegetated areas; meanwhile, effects on species richness and abundance were not significant. The results indicate that larger tidal amplitude could support more fish (both richness and abundance) in the vegetated areas, which might occur because larger tidal amplitude provides fish with access to more habitats. These results provide basic knowledge related to mangrove management at an important fish nursery ground.

Li, M.; Li, W.; Xie, M., and Xu, T., 2021. Morphodynamic responses to the Hong Kong–Zhuhai–Macao Bridge in the Pearl River estuary, China. Journal of Coastal Research, 37(1), 168–178. Coconut Creek (Florida), ISSN 0749-0208.

Human activities such as constructing large bridges, performing land reclamation, and creating harbors in complex tidal estuaries can result in severe and undesirable morphodynamic responses. This study investigates morphodynamic responses to the construction of the Hong Kong–Zhuhai–Macao Bridge (HZMB) in Lingdingyang Bay of the Pearl River estuary (LBPRE). The LBPRE in China is an important estuary with unique geomorphic features, complex hydrodynamic sediment conditions, dense shipping routes, high ship density, and a high navigation grade. The HZMB, a major sea-crossing transportation project consisting of bridges, a tunnel, and man-made islands, is being designed to cross the LBPRE. The morphodynamic responses resulting from the HZMB are likely to be significant. Therefore, it is necessary to carry out studies to optimize the HZMB design to minimize its impacts on hydrodynamics, sediment environment, harbors, and navigational channels as much as possible. In this article, the natural hydrodynamic and sediment conditions are first analyzed on the basis of in situ data. Next, a numerical model of tidal current, sediment movement, and seabed deformation based on TK-2D software is set up with an irregular triangular grid. The model is calibrated with in situ data, and the results show that the calculated tidal levels, tidal currents, suspended load concentrations, and seabed deformations are all in good agreement with field data. The model is then applied to carry out high-resolution simulations for design optimization of the HZMB from the perspective of its impacts on morphodynamics and hydrodynamics, as well as on harbors and channels. The study shows that the proposed HZMB design is feasible in terms of the morphodynamic responses. The conclusions provide an important foundation for the construction of the HZMB project.

Dong, C.; Zhao, P.; Yu, G., and Zhang, M., 2021. Laboratory flume experiments on cohesive sediment erosion by oscillating wall jet. Journal of Coastal Research, 37(1), 179–190. Coconut Creek (Florida), ISSN 0749-0208.

Jet scour, a common method of dredging clay, must be accurately estimated. Cohesive sediment is aggregated by adhesion and is sensitive to erosion when the flow shear is appended with oscillation, as indicated by sediment rheology. On the basis of sediment rheology, this study experimentally investigates the timescale of the erosion of cohesive sediment under an oscillating wall jet in a laboratory flume. The oscillating wall jet is induced by a swinging oblique impingement jet. The erosion of the cohesive sediment was performed under an oscillating wall jet with a fixed flow rate but different oscillating intensities. The morphological properties, scouring depths, and rheological characteristics of the sediment were observed. The results show that when the oscillating frequency is zero or low, the sediment particles scatter similarly to aggregates, forming ridges at the intersection of the scouring slope and bed surface. However, these aggregates and ridges disappear when the oscillating frequency increases. Further, evaluations of the cohesive sediment under different oscillating frequencies indicate that the yield stress decreases with an increase in the scouring frequency. Submerged cohesive sediments tend to fluidize under oscillating shear, which indicates shear thinning behavior. Under the conditions of the oscillating wall jet, the scouring depth of the cohesive sediment increases exponentially with the oscillating intensity.

Xu, H.; Chen, C.; Shao, Z.; Wang, Z.; Cai, L.; Li, Z., and Xu, C., 2021. Dynamic response of heavy-haul railway tunnels in fully weathered coastal red sandstone strata with base rock reinforcement: A numerical study. Journal of Coastal Research, 37(1), 191–202. Coconut Creek (Florida), ISSN 0749-0208.

Coastal fully weathered red sandstone exhibits poor cementation, and tunnels can easily develop large deformations undercrossing such rock masses under long-term cyclic loading. This article studies dynamic response of the base rock and tunnel lining structures under the dynamic load of heavy-haul train when different base rock reinforcing methods (curtain grouting reinforcement and cement-soil compaction pile reinforcement) are adopted. A tunnel undercrossing fully weathered red sandstone strata is taken as the research object, from which the rock mechanical strength parameters are obtained for a numerical model. The dynamic response of the base rock significantly decreases with the increased depth, and the inverted arch and arch foot are the most unfavorable stress locations, to which more attention should be paid. Base rock reinforcements enhance the integrity of rock mass, and the acceleration and peak stress of the rock base and lining structure significantly reduce when reinforcement is exerted. The effect of curtain grouting proved to be better, which is indicated by the reduction of acceleration and displacement of tunnel lining as well as the low value of peak acceleration and stress of the base rock.

Song, M.; Wang, Q.; Wang, S., and Zhou, L., 2021. Specialization and diversification of the marine industry and marine economic growth: An example from Chinese coastal areas. Journal of Coastal Research, 37(1), 203–215. Coconut Creek (Florida), ISSN 0749-0208.

With an increasing shortage of land resources and increasing pressure regarding population and environment, many countries and regions have turned their attention toward oceans. Based on the externality theory, this study innovatively examines how specialization and diversification affect marine economic growth. Based on the panel data of 11 Chinese coastal provinces from 2006 to 2014, the article use location entropy and diversification indexes to measure the specialization and diversification of marine industry. The study analyzes both linear and nonlinear relationships between specialization and diversification and marine economic growth. The empirical results show that both specialization and diversification have a positive influence on marine economic growth; however, diversification was found to play a more important role. This study specifically studied the differences in effects on regions with different industrial scales. The findings show that there are different U-shaped nonlinear relationships between specialization and diversification and marine economic growth under different industrial scales. Finally, this article offers implications of the study and corresponding policy recommendations for restructuring the marine industry in each area.

McGuirk, M.T.; Kennedy, D.M.; Konlechner, T., and Chiaradia, A., 2021. Quantifying changes in surface elevation in conjunction with growth characteristics of incipient and foredune vegetation. Journal of Coastal Research, 37(1), 216–224. Coconut Creek (Florida), ISSN 0749-0208.

Vegetation is critical for the initiation and growth of incipient dunes and foredunes by providing structure to entrap and store sand. Vegetation characteristics (leaf length, width, height, and quantity) directly influence the rate and volume of sand deposition and therefore the final dune morphology. This paper describes a low-cost and highly portable method to quantify changes in sand surface elevation in relation to plant growth character. A sediment elevation platform was constructed from steel and Perspex, from which surface elevation and plant character can be measured with a movable wooden dowel. This was used in conjunction with a point intercept pin frame to quantify leaf height and number of touches, from which leaf density and frequency were calculated. The system is collapsible, lightweight, and costs AUD 360. It may be operated by a single person. It was tested in a pilot study conducted at Phillip Island, Australia. Plant attributes of two dominant coastal grasses (Spinifex sericeus and Thinopyrum junceiforme) were quantified in December 2018 and January 2019, and sand elevation changes were quantified in January and February 2019. Data collected during the measurement period displayed the influence of plant growth on sand accumulation on a monthly scale. Measurements showed an increase in sand surface elevation from January to February. The average vertical sand accretion for the quadrant with T. junceiforme in January was 29 mm and in February was 89 mm, whereas S. sericeus had an average vertical sand accretion for January of 95 mm and for February of 162 mm. The number of leaves of S. sericeus increased from December (48) to January (169). This new method enables tracking of changes in sand morphology, along with the specific plant growth characteristics. This knowledge may enable the planning of specific dune morphologies using specific plant species and assist in dune recovery after erosion.